Moreover, if the integer has an odd number of digits, append a leading zero to the left side of the number so that it can flipflop with the first nonzero digit.

For example, flipflop(9876) = 8967 and flipflop(1234567) is 10325476.

warm-up:

What is the smallest positive integer such that flipflop(m) = m*4?

octuple the number:

What is the smallest positive integer such that flipflop(n) = n*8?

In the case of multiplication by 8, I have found only one solution: are there any others?